route.js

import Ember from 'ember';
import { all, task, timeout } from 'ember-concurrency';

export default Ember.Route.extend({

  serverStatusLoopTask: task(function *() {
    let { servers } = this.modelFor('servers');
    while (true) {
      yield timeout(5 * 1000);
      yield all(servers.map(::(this.get('fetchServerStatusTask')).perform));
    }
  }).on('activate').cancelOn('deactivate'),

  fetchServerStatusTask: task(function *(server) {
    yield server.belongsTo('status').reload();
  }).maxConcurrency(3)
});